Rotary work head for floor cleaning machines and the like



Dec. 29, 1970 w. N. BROWN EI'AL 3,550,179 7 ROTARY WORK HEAD FOR FLOOR CLEANING MACHINES AND THE LIKE 7 Filed Au 12. 1968 I L l' l I 44 54 E lNl/E/VTO/PS f 1 MY/VE/VEROW/V, v m 34 M/LTO/V LBfiwI/W/ 35 5% 50 52 50 Y United States Patent O US. Cl. 15-430 8 Claims ABSTRACT OF THE DISCLOSURE A rotary Work head is provided for floor cleaning machines and the like. The work head has a generally disc-shaped body with a central axis of rotation and a front face normal to the axis to which may be secured a flexible work pad, such as a floor cleaning pad. Means, such as pressure pads, are movably mounted within forwardly opening cavities in the front side of the Work head and are urged forwardly by springs into contact with the work pad to cause the latter to conform to irregularities in a work surface when the pad is driven in rotation by the work head while disposed in rubbing contact with the surface.

BACKGROUND OF THE INVENTION Field of the invention This invention relates generally to Work surface conditioning machines, such as floor cleaning machines and the like, of the class having a rotary work head mounting a work pad which is driven in rotation by the work head while disposed in rubbing contact with a work surface. The invention relates more particularly to an improved rotary work head for surface conditioning machines of the class described.

Prior art Surface conditioning machines of the class described are well known in the art and are used for a variety of purposes. The present invention is concerned primarily with floor cleaning machines of this class and will be described in connection with such a machine. It will become evident as the description proceeds, however, that the features of the invention may be embodied in rotary surface conditioning machines for other purposes.

A typical floor cleaning machine of the type to which this invention pertains comprises a two-wheeled carriage having an upwardly inclined handle to be grasped by the operator and a frame rigid on the lower end of the handle mounting a motor with a vertical shaft. Fixed to the lower end of this shaft is a rotary work head having a lower face to which is fixed a floor cleaning pad. During operation of the floor cleaning machine, the motor is energized to drive the Work head and pad in rotation. The carriage is then Wheeled back and forth across a floor to be cleaned with the work pad disposed in rubbing contact with the floor. A suitable cleaning solution, such as a detergent or wax, is applied to the floor, whereby rotation of the work pad in rubbing contact with the floor cleans and/or polishes the latter.

While the existing floor cleaning machines of the character described are satisfactory to a degree, they possess certain inherent deficiencies which this invention seeks to overcome. One of the primary disadvantages of the existing machines, for example, resides in the fact that they are ill-suited to cleaning floors with depressions or other irregularities. This is because the work pads of such machines generally seat flat against the rotary work head and are thus prevented from conforming closely to the local contour of the floor surface. Some floor cleaning machines have been devised to overcome this dis advantage. Exemplary of floor cleaning machines of this type are those disclosed in prior art Patent Nos. 1,67 3,160 and 3,183,542. While the latter floor cleaning machines alleviate, to some extent, the above noted disadvantage of most conventional floor cleaning machines, they are not totally satisfactory for the reason that even their work pads fail to conform accurately to irregular floor surface contours. Moreover, the work heads of such machines tend to be complex in construction and costly to manufacture.

SUMMARY OF THE INVENTION The present invention provides an improved rotary work head for machines of the class described, particularly floor cleaning machines, which avoids the above noted and other disadvantages inherent in the work heads of the existing machines. In general terms, the present improved rotary work head comprises a generally discshaped body having a central axis of rotation and a front face normal to the axis. Mounted on the work head are means for securing a flexible floor cleaning pad, or other flexible work pad, to the front face. According to a primary feature of the invention, the work head mounts a number of spring-loaded means which are spaced about the front face of the head and press yieldably against the work pad in such a way as to cause the latter to conform accurately to local irregularities in a work surface when the pad is driven in rotation with the work head while disposed in rubbing contact with the surface. According to a further feature of the invention, the spring-loaded means are mounted within forwardly opening cavities in the front side of the work head so that they may retract rearwardly against spring action to permit the work pad to seat flat against the front face of the work head when rubbing a relatively flat Work surface. In the particular embodiment of the invention which has been selected for presentation in this disclosure, the springloaded means of the work head comprises pressure pads which are slideably supported on bearing posts extending forwardly through the cavity and are urged forwardly by coil springs surrounding the posts.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a typical floor cleaning machine embodying an improved rotary work head according to the invention;

FIG. 2 is an enlarged bottom view of the work head looking in the direction of the arrows on line 2-2 in FIG. 1, with a portion of the work pad, or floor cleaning pad, broken away for the sake of clarity;

FIG. 3 is an enlarged section taken on line 33 in FIG. 2;

FIG. 4 is a section taken on line 44 in FIG. 3; and

FIG. 5 illustrates a modified pressure pad which may be installed in the present work head.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, and particularly to FIGS. 1 through 4, there is illustrated a floor cleaning machine 10 which is generally conventional, except for the present rotary work head 12 which is installed on the machine. Accordingly, the floor cleaning machine 10 will be described only in sufiicient detail to enable a full and complete understanding of the present invention. With this in mind, the floor cleaning machine comprises a carriage 14 with two supporting wheels 16 (only one visible) fixed to the lower end of a generally upright, upwardly and rearwardly sloping handle 18. Mounted on the upper end of this handle is a handlebar 20 adapted to be grasped by the operator for moving the carriage 14 back and forth on a floor to be cleaned. Fixed to the lower end of the handle 18 is a frame 22. A hollow circular, downwardly opening housing 24 is secured to the underside of the frame. Mounted on the upper side of the frame, in coaxial relation with the housing 24, is a motor 26 having a lower, normally vertical shaft (not shown). The motor is equipped with an electrical cord (not shown) adapted to be plugged in a wall receptacle for energizing the motor. The motor is turned on and off by means of a switch lever 28 on the handlebar 20.

The floor cleaning machine 10, as thus far described, is conventional. The present invention resides in the rotary work head 12 which is secured to the lower shaft of the motor 26. Work head 12 has a disc-shaped body 30 with a central axis 32 of rotation. The front side of the body provides a fiat face 34 normal to the axis 32. Mounted on the rear side of the body are means (not shown) for securing the body to the shaft of the motor 26. It will now be understood, therefore, that when the work head 12 is installed on the floor cleaning machine 10, the front face 34 of the work head body 30 is presented downwardly, toward the floor to be cleaned. Positioned against the front face 34 is a work pad 36, which in this instance is a conventional floor cleaning pad composed of nylon, steel wool, or other suitable material. The work pad is circular in shape and has substantially the same diameter as the work head body 30. Means 38 are provided for securing the work pad to the body. Various means may be employed for this purpose. In this case, the pad mounting means 38 comprise fabric mounting strips, such as adhesive strips.

According to a primary feature of the invention, the work head 12 is equipped with a number of springloaded means 40 which are mounted on the work head body 30, in spaced relation about the body face 34. These spring-loaded means are urged forwardly by spring pressure against the work pad 36 and serve to cause the pad to conform accurately to the contour of the floor surface being cleaned when the pad is driven in rotation with the work head while disposed in rubbing contact with the surface. The particular spring-loaded means 40 illustrated comprise pressure pads 42 and coil springs 44 which act between the work head body 30 and the pads to urge the latter forwardly against the work pad 36. According to a further feature of the invention, the pressure pads 42 and their biasing springs 44 are contained within cavities 46 in the work head body 30 which open forwardly throuhg the body face 34. This arrangement permits the pressure pads to retract rearwardly against the action of their springs to positions wherein the work pad 36 seats flat against the body face 34 to permit the work pad to conform accurately to a generally flat floor surface.

Referring now in greater detail to the illustrated springloaded means 40, the latter are four in number and are identical in construction. Accordingly, a description of one will sufiice for all. The work head cavities 46 are uniformly spaced about the rotation axis 32 of the work head 12 and are elongated in a radial direction of the head. Secured to the bottom wall of each cavity, along the radial side thereof, are a pair of bearing posts 48 which extend forwardly through the cavity. Fixed to the outer ends of each pair of posts is a shoulder plate 50' which extends the full length of the respective cavity and is recessed into the front face 34 of the work head body 30 so as to be substantially flush with this face. Each pressure pad 42 comprises an elongate pressure bar 52 which extends the full length of the respective work head cavity 46, in the region between the corresponding bearing post shoulder plates 50. In this instance, each pressure bar 52 has a generally channel shape in transverse cross section. Fixed to the rear side of each pressure 'bar 52, adjacent the ends of the bar, is a guide or bearing plate, 54 which extends crosswise of the work head cavity 46. The ends of these bearing plates are apertured to slide on the bearing posts 48. The coil springs 44 are disposed in surrounding relation to the bearing posts, between the bottom of the work head cavity 46 and the bearing plate 54. It is now evident, therefore, that the springs 44 urge the pressure pads 42 forwardly to positions wherein the pressure bars 52 of the pads project forwardly of the front work head face 34. The pressure pads are retractable rearwardly against the action of the springs to positions wherein the front surfaces of the pressure bars are flush with the work head face.

In the embodiment of the invention illustrated in FIGS. 1 through 4, the front work pad engaging surfaces of the pressure bars 52 are generally flat. FIG. 5 illustrates a modified pressure pad 42a which may be embodied in the present Work head. This modified pressure pad has a pressure bar 52a with a rounded front surface.

In operation of the floor cleaning machine 10, the rotary work head 12 is installed on the shaft of the motor 26 and the latter is energized to drive the work head, and its work pad 36, in rotation. The machine is then wheeled back and forth across a floor to be cleaned while the work pad 36 is retained in rubbing contact with the floor surface. The reaction pressure thereby exerted against the pad tends to retract the pressure pads 42 rearwardly against the action of their springs 44. In the event that the portion of the floor surface being cleaned is substantially fiat, the pressure pads will normally be retracted to positions wherein the work pad 36 seats fiat against the front face 34 of the work head body 30. Assume now that movement of the floor cleaning machine across the floor brings the work pad 36 into contact with a portion of the floor containing a depression or other irregularity. In this case, the constant pressure exerted by the pressure pads 42 against the work pad 36 causes the latter to conform accurately to the irregular contour of the floor surface as the work pad traverses the surface. Thus, under the conditions just mentioned, the pressure pads 42, and the portions of the work pad 36 engaged by the pressure pads, will oscillate back and forth as the work pad rotates over the irregularity. It is now evident, therefore, that the present floor cleaning machine is uniquely adapted to clean and polish floors with depressions or other irregularities without tipping of the floor cleaning machine as is presently required with the existing machines. The relatively fiat pressure bar configuration of FIG. 4 is particularly suited for relatively large area depressions or other floor irregularities. The modified .pressure bar configuation of FIG. 5 is best suited to cleaning floors with more pronounced irregularities.

While the invention has been described in connection with certain presently preferred embodiments thereof, various modifications of the invention are possible within the spirit and scope of the following claims.

What is claimed as new in support of Letters Patent is:

1. A rotary work head for floor cleaning machines and the like comprising:

a generally disc-shaped body having a central axis of rotation, a generally flat front face normal to said axis adapted to be presented toward a work surface to be rubbed, and means to couple said body to a motor for driving said body in rotation on said axis,

means on said body for securing to said body face a flexible work pad to be placed in rubbing contact with said work surface while said body is driven in rotation, and

a number of separate resiliently yieldable pressure pads mounted within forwardly opening cavities entering and spaced about said body face for exerting localized forward spring forces on said work pad to cause said work pad to conform to irregularities in the work surface, said pressure pads being yieldable toward said body to permit said work pad to seat fiat against said body face.

2. A work head according to claim 1 wherein: said pressure pads comprise rigid pressure plates and springs acting between said body and said pressure plates for urging the latter forwardly relative to said body.

3. A work head according to claim 2 wherein: said pressure plates are uniformly spaced about and are elongated radially of said axis.

4. A work head according to claim 2 including:

bearing posts fixed to and extending forwardly from the bottom of each cavity, and

guides on each pressure plate slidable on the corresponding bearing posts.

5. A work head according to claim 4 wherein:

said springs are coiled springs which encircle said bearing posts,

said bearing posts have forward shoulder means substantially flush with said body face for limiting forward extension of said pressure plates under the action of said springs, and

said pressure plates comprise pressure bars extending forwardly from theid respective guides for contact with said work pad.

6. A rotary work head for floor cleaning machines and the like comprising:

a generally disc-shaped body having a central axis of rotation, a generally flat front face normal to said axis adapted to be presented toward a work surface to be rubbed, and means to couple said body to a motor for driving said body in rotation on said axis,

means on said body for securing to said body face a flexible work pad to be placed in rubbing contact with said work surface while said body is driven in rotation,

a number of separate resiliently yieldable pressure pads mounted within forwardly opening cavities entering and spaced about said body face and springs acting between said pressure pads and body for urging said pressure pads forwardly and thereby exerting localized forward spring forces on said work pad to cause said work pad to conform to irregularities in the Work surface, said pressure pads being yieldable toward said body to permit said work pad to seat flat against said body face,

bearing posts fixed to and extending forwardly from the bottom of each cavity,

guides on each pressure plate slidable on the corresponding bearing posts,

said springs encircling said bearing posts,

said bearing posts having forward shoulder means substantially flush with said body face for limiting forward extension of said pressure pads under the action of said springs,

said pressure pads comprising pressure bars extending forwardly from their respective guides for contact with said work pad,

said cavities being uniformly spaced about said axis and are elongated in the radial direction of said body,

said bearing posts being disposed along opposite radial sides of each cavity,

said shoulder means comprising shoulder plates extending along opposite radial sides of each cavity and joined to the forward ends of the adjacent bearing posts,

said guides comprising bearing plates extending crosswise of said cavities and having apertured ends slidable on the respective bearing posts,

each said pressure pad further comprising a pressure bar extending lengthwise of the respective body cavity between the corresponding bearing post shoulder plates and secured to the respective bearing plates, and

said pressure bars being projectable forwardly of said body face by spring pressure.

7. A work head according to claim 6 wherein: the

front surfaces of said pressure pads are rounded in transverse cross section.

8. A work head according to claim 6 wherein: the

front surfaces of said pressure pads are generally fiat in transverse cross section.

References Cited UNITED STATES PATENTS 2,713,757 7/1955 Brennecke 5ll77 3,068,503 12/1962 Jepson et al. 15-49 FOREIGN PATENTS 66,087 6/1913 Switzerland 15-50 WALTER A. SCHEEL, Primary Examiner L. G. MACHLIN, Assistant Examiner US. Cl. X.R. 

